True potato beetles are members of the genus Leptinotarsa, with more than 40 species throughout North and South America, including at least 10 species found north of Mexico. While most species north of Mexico are found in the southwestern United States, two species are found either in the eastern states or throughout most of the United States (Arnett 2002). The more notable of these two is the Colorado potato beetle, Leptinotarsa decemlineata (Say), which is a serious pest of potatoes and other solanaceous plants.

The Colorado potato beetle was first discovered by Thomas Nuttal in 1811. and described in 1824 by Thomas Say from specimens collected in the Rocky Mountains on buffalo-bur, Solanum rostratum Ramur. The insect’s association with the potato plant, Solanum tuberosum (L.), was not known until about 1859 when it began destroying potato crops about 100 miles west of Omaha, Nebraska. The insect began its rapid spread eastward, reaching the Atlantic Coast by 1874.

The evolution of the name Colorado potato beetle is curious because the beetle is believed to have originated in central Mexico, not Colorado. It had a series of names from 1863 to 1867, including the ten-striped spearman, ten-lined potato beetle potato-bug, and new potato bug. Colorado was not associated with the insect until Walsh (1865) stated that two of his colleagues had seen large numbers of the insect in the territory of Colorado feeding on buffalo-bur. This convinced him that it was native to Colorado. It was Riley (1867) who first used the combination Colorado potato beetle.

Distribution (Back to Top)

The Colorado potato beetle, Leptinotarsa decemlineata (Say), occurs in Mexico and in most of the United States (except Alaska, California, Hawaii, and Nevada), including Florida. It was first reported in Florida in 1920, but it is not often a major pest. It also occurs in southern Canada and is a pest in Central America. The species has been introduced into Europe and parts of Asia (Capinera 2001).

The false potato beetle, Leptinotarsa juncta (Germar), is found primarily in the eastern United States from northern Florida to eastern Texas (with only Sabine County reported as of 2005) (Quinn 2008), north to Missouri, southern Illinois and Indiana, and east to Maryland, West Virginia, and Virginia.

Description (Back to Top)

The genus Leptinotarsa is assigned to the tribe Doryphorini containing three genera in the United States, recognized by having the procoxal cavities open behind, and simple claws separate at the base and usually divergent. Species of Leptinotarsa are recognized by the following features: maxillary palpi (mouthparts) with apical segment shorter than preceding, truncate; mesosternum not raised above the level of prosternum; profemur of male simple.

Two species of Leptinotarsa occur in Florida: Leptinotarsa decemlineata, the Colorado potato beetle, and Leptinotarsa juncta, the false potato beetle. The latter incorrectly has been called the false Colorado potato beetle because of its similarity to Leptinotarsa decemlineata.

Adults: The adults measure about 3/8 inch long and are yellowish-orange with multiple black stripes down the back with five per elytron (Wilkerson et al. 2005). They are robust and oval in shape when viewed from above. The head has a triangular black spot and the thorax has irregular dark markings (Capinera 2001).

In Leptinotarsa decemlineata, the pale yellow elytra are outlined in black, with each elytron having five vittae (broad longitudinal stripes). Vitta 1 is shorter than other four and adjacent to the sutural margin. Vittae 2 through 5 extend more than half the length of the elytron and are very distinct. Elytron punctation is coarse in irregular rows. The underside of the beetle and the legs are mostly dark (Capinera 2001).

In Leptinotarsa juncta, each pale yellow elytron has five black vittae (broad longitudinal stripes), with vitta 1 bordering sutural margin and extending from just below the base to the apex. Vitta 2 is shorter than the first, not reaching the base. Vitta 3 and 4 connect at the apex of the elytron with space between black. Vitta 5 is along the lateral margin of the elytron. Punctation is coarse, in very regular rows outlining each vitta. There is a distinct black spot on the outer margin of the femur. The legs are mostly orangish in color.

Eggs: The eggs are bright orange and football-shaped, about 1.7-18 mm long and 0.8 mm wide. Females use a yellowish adhesive to deposit eggs on the lower surface of the foliage in clusters of five to 100, but 20 to 60 eggs is more common. The larva becomes visible in the last 12 hours before hatching. Under field conditions, females can lay 200-500 eggs, but this may be an underestimate (Capinera 2001). The eggs of the false potato beetle are slightly larger, and fewer are found in a cluster.

Larvae: The small, cyphosomatic (dorsal and ventral surfaces distinctly nonparallel), reddish larvae of the Colorado potato beetle are 1/2 inch long when mature. The larvae typically have two rows of black spots down the sides. The larvae are very plump and the abdomen is strongly convex. Larvae bear a terminal proleg at the tip of the abdomen as well as three pairs of thoracic legs. (Capinera 2001).

Figure 6. Larva of the Colorado potato beetle, Leptinotarsa decemlineata (Say). Photograph by University of Florida.

False potato beetle larva are generally paler (almost white) and have one row of black spots.

Pupae: Mature larvae burrow 2-5 cm into the soil, and after about two days begin to pupate. Colorado potato beetle pupae are oval and orangish in color. The mean development time is about 5.8 days (Capinera 2001).

Life Cycle (Back to Top)

The life cycle of the Colorado potato beetle starts with the adult as the overwintering stage and can be as short as 30 days (Capinera 2001). Adults dig into the soil to a depth of several inches and emerge in the spring. They feed on newly sprouted host plants where they mate.

Females deposit eggs on the surface of the host plant’s leaves, usually on the undersurface protected from direct sunlight. Overwintering adults usually feed for five to 10 days before mating and producing eggs (Capinera 2001). Adult females deposit over 300 eggs during a period of four to five weeks. Eggs hatch in four to 10 days depending in part on temperature and humidity (Capinera 2001).

The four larval instars last a total of 21 days. The larvae feed almost continuously on the leaves of the host plant, stopping only when molting.

Larvae drop from the plants and burrow into the soil where they construct a spherical cell and transform into yellowish pupae. This lasts from five to 10 days. There are one to three generations per year, depending on latitude; however two generations can occur even as far north as Canada. In the south, the third generation usually feeds on weeds and is often overlooked (Capinera 2001).

The life cycle of the false potato beetle is similar to that of the Colorado potato beetle. Eggs hatch in four to five days and the larvae feed on the leaves of the host plants. There are four larval instars lasting 21 days. The larvae drop to the soil to pupate, and pupation lasts 10 to 15 days.

Hosts (Back to Top)

Potatoes are the preferred host for the Colorado potato beetle, but it may feed and survive on a number of other plants in the family Solanaceae, including belladonna, common nightshade, eggplant, ground cherry, henbane, horse-nettle, pepper (rarely), tobacco, thorn apple, tomato, and, its first recorded host plant, buffalo-bur. The Colorado potato beetle has displayed an ability to adjust its host range to locally abundant Solanum species. Colorado potato beetles also feed on non-solanaceous plants, but this is rare and these plants should not be considered normal hosts (Capinera 2001).

The false potato beetle is found primarily on the common noxious weed, horse-nettle, Solanum carolinense L. It also feeds on other solanaceous plants, such as species of ground cherry or husk tomato, Physalis spp., and nightshade, Solanum spp.

Management (Back to Top)

Sampling. Entire plants should be examined for above-ground life stages. The adults are attracted to the color yellow and can be captured with traps. However, traps are seldom used because the various life stages are so apparent on plants (Capinera 2001).

Cultural control. The Colorado potato beetle may be managed culturally by crop rotation or destruction of crop debris. Distances of at least 0.5 km are required to provide protection if crops are rotated. Beetles initially disperse by walking, so crop rotation and/or trenching can significantly reduce infestations. Trenches with 45° or greater slope can capture 50% or more of the beetles (Capinera 2001).

Biological control. While many natural enemies have been idenitifed, they are usually not able to control Colorado potato beetle populations below the necessary levels. Among these natural enemies are predators such as green lacewings, several predatory stink bugs and the spined soldier bug. The most important parasitoid is the tachinid fly Myiopharus doryphorae (Riley) which builds to high densities in the autumn, affecting the last generation of beetles. In Colorado, parasitism rates are high early in the season and prevent Leptinotarsa decemlineata from becoming a serious pest (Capinera 2001).

Chemical control. Insecticides are commonly used to control populations of Colorado potato beetle, but resistance to insecticides develops rapidly (Wilkerson et al. 2005). Some strains of the bacterium Bacillus thuringiensis are effective but it must be applied to the first two instars to be effective (Capinera 2001).

An Equal Opportunity Institution Featured Creatures Editor and Coordinator: Jennifer L. Gillett-Kaufman, University of Florida

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Wild Fact #505 – Mmmmmm….French Fries! – Colorado Potato Beetle

Colorado Potato Beetle — Photo Courtesy of L. Carter

Now I know we tend to be sluggish on Monday mornings but I think this is a great opportunity for a Pop Quiz. You know, it will get those brain cells of yours working. Last week, I mentioned that we would have a theme for this week of Wild Facts. The first animal we are looking at is the Colorado Potato Beetle so your one question Pop Quiz is this. What is the theme for the week? Let’s learn a little more about the Colorado Potato Beetle as you think about your answer.

The Colorado Potato Beetle is also known as the Colorado Beetle, Ten-Striped Spearman, Ten-Lined Potato Beetle, and of course the Potato Bug. No matter what you decide to call them, these insects are about 10 mm (0.4″) long and have a beautiful yellow/orange colour broken up by 5 dark coloured lines. Wait a minute! If they only have 5 dark lines, why are they called the Ten-Lined Potato Beetle? That is a good question but shouldn’t you be focusing on your pop quiz? Obviously, if you count the dark and light lines, it equals ten…. At least I hope it does.

Controlling the population of the Colorado Potato Beetle may be tough since the females tend to be very prolific, laying up to 800 eggs. Instead of putting all of their “eggs” in one basket, the Potato Bug will generally lay batches of 30 eggs in any single location. Don’t worry, I did the math for you and that is about 27 batches of eggs they will lay. Normally these eggs hatch anywhere between 4 and 15 days; however, this is largely dependant on the temperature and the amount of light. If the conditions are not appropriate than these eggs will enter a stage called diapause, which is a fancy way of saying they will delay their hatching until spring.

Prolific Potato Beetles — Photo Courtesy of L. Carter

So why would you want to try and control these colourful little Potato Bugs? As you may have guessed by now, the Colorado Potato Beetle is a major pest of lettuce……what did you think I was going to say? Okay, you are right, they destroy potato crops but may also damage tomatoes and egg plants. No matter what your opinion is on the use of insecticide, you would think this would be an effective way to remove these pests from your garden, right? Wrong! The Potato Bug is capable of rapidly building up an immunity to insecticides. Even introducing natural predators doesn’t work too well since this pest is so prolific, with their 800 eggs and all. So how do they control these insects? Well, there really isn’t an amazing way to do it, so if you can find a cost effective way to remove the Potato Bug, I guarantee you will become quite wealthy.

All right, that does it for the first Fact of our themed week. Oh, I guess I have to mark your quiz before we leave. If you “guessed” this weeks theme to be Garden Pests or something similar then you get a sticker! See you tomorrow for the next pest.

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Colorado Potato Beetle

The Colorado Potato Beetle is a species of arthropods that are considered as pests throughout their range. They are mostly found active, infesting thousands of acres of crop fields, especially potatoes, which is their preferred host plant. Several measures have been taken to prevent these creatures from this act of destruction; however, treatment of these arthropods in home gardens can be more challenging.

Table of Contents

Colorado Potato Beetle Scientific Classification

Kingdom:

Animalia

Phylum:

Arthropoda

Class:

Insecta

Order:

Coleoptera

Family:

Chrysomelidae

Genus:

Leptinotarsa

Species:

L. decemlineata

Scientific Name:

Leptinotarsa decemlineata

Table Of Content

Table of Contents

Scientific Classification

Colorado Potato Beetle

Kingdom:

Animalia

Phylum:

Arthropoda

Class:

Insecta

Order:

Coleoptera

Family:

Chrysomelidae

Genus:

Leptinotarsa

Species:

L. decemlineata

Scientific Name:

Leptinotarsa decemlineata

Physical Description

Size: The total length of the body (head to the tip of the abdomen) is approximately 10 millimeters (0.39 in), and around 3 millimeters (0.12 in) in width.

Weight: They can weigh anything between 50 and 170 mg.

Body: The shape is rounded, with yellowish-orange coloration on the exoskeleton (cover) with black longitudinal stripes on the wings, and a few black spots behind the head, from where, two dark brown antennae, with uneven tips, protrude out.

Feet: Three pairs of feet with yellowish tinge at the top and black to dark brown at the tips.

Sexual Dimorphism: Not present.

Lifespan/Longevity

In the wild, the typical lifespan of these insects is between 2 and 12 months.

Distribution/Range & Habitat: Where do Colorado Potato Beetles Live

Colorado potato beetles live in the temperate and terrestrial suburban agricultural fields, grasslands, gardens. Native to a small region in western North America, they have spread very quickly in the potato crops across the other parts of America, Europe, and Asia, totaling an area of over 16 million sq. km.

Behavior

The primary means of their communication and perception are smell and vision. They select and find out their nearby host plants through the chemical signals emitted by the latter. The creatures also retain their sexual communication by means of these signals.

Studies show that the adult potato beetles can sense the wavelengths between yellow and ultraviolet, as also polarized lights. When an individual male is done with selecting its host, it emits its ‘aggregation pheromone’, with which both the males and the females (and even the nearby larvae) get attracted to in the same location. Before mating, the females secrete a sex pheromone in order to attract the males.

Diet: What Do Colorado Potato Beetles Eat

As their name suggests, the preferred and primary host of the Colorado potato beetle is the potato plant; however, they may also feast upon a number of other plants as well, including crop plants like tomato, tobacco, eggplant, and pepper.

Colorado Potato Beetle Pictures

Colorado Potato Beetle Images

Reproduction and Life Cycle

The Colorado potato beetle has a polygynandrous (promiscuous) mating system. They choose multiple partners when the breeding season checks in. After the winter months, they become active usually around the springtime in May, and begin mating and infesting the crop fields and gardens. The adult beetles feed for a very short period of time before mating.

The female Colorado potato beetle lays the eggs on the undersurface of the leaves of their host plant so as to protect them from direct sunlight. They deposit over 300 eggs within a span of four to five weeks.

Depending upon the temperature and latitude, the eggs hatch in about 4 to 10 days, from which the larvae are born, with their four instars lasting for around 21 days. These insects would feed on the leaves of the host plant, almost continuously, only stopping during molting.

Before pupating, the larva drops into the soil from the plants and make a spherical cell while metamorphosing into a yellowish pupa. This stage lasts for about 5 to 10 days. The arthropods have 1 to 3 generations every year.

Colorado Potato Beetle Eggs

Colorado Potato Beetle Larvae

Adaptations

Their body color is almost the same as the potato skin, thus keeping them camouflaged in between piles of crops.

Predators

Several species of spiders, larger beetles and bugs have been known to eat these creatures.

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Colorado potato beetle

Colorado potato beetle

Scientific classification

Kingdom:

Animalia

Phylum:

Arthropoda

Class:

Insecta

Order:

Coleoptera

Suborder:

Polyphaga

Family:

Chrysomelidae

Genus:

Leptinotarsa

Species:

L. decemlineata

Binomial name

Leptinotarsa decemlineataSay, 1824 [1]

The Colorado potato beetle, Leptinotarsa decemlineata, is a beetle. It is sometimes just called the Colorado beetle. It is one of the worst potato pests in the world.

The beetle is notable for its ability to resist pesticides. Over the last 50 years it has become resistant to 52 chemical compounds used in insecticides, including cyanide. [2] However, not every population is resistant to every chemical. [3]

The Colorado beetle first lived in the southwest United States and northern Mexico. Now it lives in most of North America and also in Europe and Asia.

Contents

What it eats

The Colorado potato beetle now eats cultivated potato plants. Both larvae and adults eat the leaves and strip the plant down to a skeleton. They may also attack tomato and eggplants. There can be so many Colorado potato beetles in potato farms that they destroy the potatoes.

Defence

Because the beetle rapidly evolves resistance to chemicals, the best defence may be biological control. A ground beetle, Lebia grandis is a predator of the eggs and larvae, and its larvae are parasitoids of the Colorado beetle’s pupae.

Beauveria bassiana (Hyphomycetes) is a pathogenic fungus that infects many insects, including the Colorado beetle. It is probably the most widely used natural enemy of the Colorado beetle. There are commercial formulations that can be applied using a pesticide sprayer.

Origins

The Colorado potato beetle did not always eat potato plants. This is because potatoes came from South America, not near the beetle’s original range. Before people brought potatoes to North America, the Colorado beetle ate a plant called buffalo-bur.